The overall goal of the Human Immunology Project Consortium (HIPC) program is to capitalize on recent advances in immune profiling methods in order to create a novel public resource that characterizes diverse states of the human immune system. We propose to contribute to this program through deep interrogation and a broad systems approach that will identify molecular signatures of divergent human immune responses to infections. The three projects that comprise our U19 each leverage a common experimental infrastructure to focus on a different infectious diseases: the Lyme disease spirochete Borrelia burgdorferi, emerging arthropod-borne West Nile virus, and effects of aging on vaccination against influenza. Our goal is to delineate human immune signatures that are associated with the divergent manifestations in the population, using well-defined patient cohorts and a multidimensional analytical approach to quantitatively assess primary human immune cell function. Our program employs cutting-edge immune profiling such as multidimensional profiling by CyTOF, metabolomics, nanoscale technologies such as MuSIC (MultiSpectral Imaging Cytometry), and RNA-seq on single cells that will inform a systems approach to elucidate the biologic signatures defining immune responsiveness. Commonalities between the responses in different tissues, and to the different infection types, will be determined by quantifying signature enrichments, and by identifying conserved active sub-networks in this immune-specific functional network. This collaborative U19 takes advantage of enormous strengths across our institutions to tackle a challenging issue in human immunology. The investigators in this proposal have established collaborations, regular interactions, and a track record of shared success. Our three research projects are supported by shared cores for Administration, Data Management and Analysis, Single Cell Immunophenotyping, and Clinical Recruitment. The united goal of these varied approaches is to define elements of the immune response that contribute to divergent infection outcomes. This multifactorial, wide-angle view of the immune response will be compiled employing the expertise of each individual approach for Systems Modeling from deep interrogation of three sets of stratified patient cohorts. The output of this functional systems immunology approach will be definitions of human immune signatures following multiple forms of infectious challenges with the ultimate goal of defining future targets for intervention and predicting susceptibility or resistance.